Disclosed herein is a seat frame for a vehicle seat, and particularly, a seat frame for a vehicle seat in which a reclining mechanism and an actuator for driving the reclining mechanism are attached to each of side frames disposed at both right and left ends of a seat back frame.
In a reclining mechanism which rotates a seat back with respect to a seat cushion in a seat frame for a vehicle seat, there is known an electric reclining mechanism which is operated by a driving force applied from an actuator as another member (for example, see Japanese Patent Document No. 2006-306188 A (“the '188 Document”).
The reclining mechanism disclosed in the '188 Document includes a shaft which penetrates a reclining mechanism body, and the shaft is inserted in a through-hole formed in a side frame. An actuator which is disposed at an inner side of each of the right and left side frames is attached to a portion of the shaft which protrudes from the through-hole. Here, an output shaft of the actuator is engaged with the shaft. Thus, when the actuator is driven, the output shaft rotates along with the shaft, and hence the driving force generated from the actuator is transmitted to the reclining mechanism.
In the reclining mechanism disclosed in the '188 Document, the actuator is fixed to a predetermined portion of the seat frame by a bolt in order to regulate the rotation of the actuator when the actuator is driven.
As illustrated in the '188 Document, the reclining mechanism is generally attached to each of the side frames disposed at both right and left ends of the seat back frame, in particular, to lower ends connected to a seat cushion frame. Further, in the '188 Document, a bolt hole is formed in the vicinity of the arrangement space of the actuator in the side frame in order to fasten the bolt for stopping the rotation of the actuator to the side frame. In addition, in the '188 Document, a reinforcement bracket is bonded to a portion of the side frame, which is provided with the bolt hole.
In the case where the reinforcement bracket is bonded to the side frame, it is desirable that the reinforcement bracket can be easily attached to the side frame. However, in the case of bonding the reinforcement bracket to the side frame, there is a concern that the shaft rotating to drive the reclining mechanism may interfere with the reinforcement bracket. Thus, the reinforcement bracket is required to have a shape to be easily bonded to the side frame while avoiding the interference with the shaft.
Further, it is desirable that the number of components of the vehicle seat is small as much as possible. For this, it is beneficial to decrease the number of components in the structure where the reinforcement bracket is provided.
Further, in the case of bonding the reinforcement bracket to the side frame by welding, the welding area needs to be set so that the positional relation between the bolt for fixing the actuator and the shaft is stable without varying. It is desirable to set the welding area between the reinforcement bracket and the side frame so that the welding operation is easily performed.
Further, there is a need to ensure the rigidity of the reinforcement bracket itself in order to stabilize the bonded state between the reinforcement bracket and the side frame. For that reason, it is beneficial to secure the rigidity of the reinforcement bracket while considering the interference of the reinforcement bracket with respect to the actuator during the attachment of the actuator.
Moreover, in the case where a rotation shaft of an armrest is supported by the side frame in the vehicle seat equipped with the armrest, there is a need to provide the reinforcement bracket in consideration of the load generated in the side frame by the rotation of the armrest.